To build a new product the cost is around 1 million US dollars. If you spend anything below that amount you won't get a quality product anyways. If you want to successfully get investment from VC or PE, this is the minimal cost to spend on your own.
Cost for making a product include the costs of
Unique design and name;
Marketing through the channel;
Although it is possible to get a product through the ODM/OEM route, or get a MVP (minimal viable) for just a few thousand dollars, it is not likely to create a long lasting business or a growable business.
The cost of a product is relative to the competition. It will remain roughly the same for anything because you need to beat competition.
A good industry design would take approximately 3 months and 4000 US dollars.
Quality means two things. One is product repeatability of performance, another is defects. Many products are not defective but simply non-repeatable. To get precision engineering of repeatable performance takes 1 year of research by a team of two really highly talented people. Their equivalent salary is around 200,000 dollars, in any country.
There is no shortcuts. You can build a "NEW" thing but there is no buyer. You can build an "Old item" but the competitions have all staked out grounds.